It is known in the prior art to provide an apparatus, such as a lawn mower, which is air-supported and thus does not require ground wheels and axles and other parts normally used for supporting the apparatus on the ground. Generally, such devices include a substantially-enclosed housing and means for generating air pressure within the housing to provide an air cushion to float the housing over a support surface. Examples of such devices are shown in U.S. Pat. Nos. 3,170,276, 3,293,836 and 4,245,455, and U.K. Patent Specification No. 1,534,021.
While air-floated devices of the prior art have significant advantages over conventional wheeled products, such devices have certain inherent problems which have yet to be overcome. In particular, such devices typically include an outer housing having a narrow peripheral edge, bezel or seal. During operation, air blown toward the ground by the air pressure means tends to escape from the housing between the ground an the narrow edge structure, which substantially reduces the lifting force on the housing. The rapid escape of air along the periphery of the mower housing also stirs up dust and debris when mowing around shrubbery and the like, which makes mowing difficult and hazardous. Also, because the air is blown downward to keep the housing afloat, the air pressure depresses the grass, causing the cutting blade to leave an uneven cut. Other problems include the inability to maintain lateral or side-to-side stability of the device.
Perhaps the greatest disadvantage of prior art air-cushioned mowers is their inability to discharge grass cuttings, which leaves a windrow of cuttings that must be raked up after mowing. Conventional lawn mowers tend to vacuum up grass by the rotary action of the cutting blade. In prior art air-cushioned mowers, however, downwardly blown air pressure used to create the lifting force by ground effect is not sufficient to effectively discharge grass cuttings. In other words, prior art air-cushioned mowers have not been able to maintain flotation while simultaneously discharging grass clippings from a port.
It would therefore be desirable to provide an improved air-floated apparatus that overcomes these and other problems associated with the prior art.